Gasohol production by extraction of ethanol from water using gasoline as solvent. Stephen A. Leeper, and Phillip C. Wankat. Ind. Eng. Chem. Process Des. Gasohol Production – Free download as Powerpoint Presentation .ppt /.pptx), PDF File .pdf), Text File .txt) or view presentation slides online. The experiment simulated a 3-stage countercurrent extraction process. The experimental results showed gasohol with more than 10% (w/w).
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In this work we demonstrate efficient quality control of a variety of gasoline and ethanol gasohol blends using a multimode interference MMI fiber sensor.
The operational principle relies on the fact that the addition of ethanol to vasohol gasohol blend reduces the refractive index RI of the gasoline.
Since MMI sensors are capable of detecting small RI changes, the ethanol content of the gasohol blend is easily determined by tracking the Expdriment peak wavelength response.
The sensor can also distinguish when water incorporated in the blend has exceeded the maximum volume tolerated by the gasohol blend, which is responsible for phase separation of the ethanol and edperiment and could cause serious engine failures. Since the MMI sensor is straightforward to fabricate and does not require any special coating it is a cost effective solution for real time and in-situ monitoring of the quality of gasohol blends. In the last two decades there has been a growing interest in the development of renewable fuels that might replace or reduce the use of gasoline.
This has gassohol motivated by the fact that petroleum is not a renewable source, and the neverending basohol in production costs, as well as pollution problems related to gasoline use in the majority of automotive vehicles.
Among the different approaches to develop renewable fuels, ethanol has attracted significant interest because it can be used either as a replacement or an additive for gasoline. The mixture of gaohol and ethanol is known as gasohol. The experiemnt advantage when using gasohol is that the higher oxygen content of ethanol allows for greater fuel economy and reduction of contaminant emissions [ 1 — 3 ].
As a result, gasohol with different gasoline and ethanol mixtures are currently gasoho, in different countries. Nevertheless, there are some issues that need to be taken into account when using gasohol in small engines. Due to the hygroscopic and miscibility properties of ethanol, water can be absorbed from atmosphere and it dilutes the ethanol. The main issue here is that if we have a higher fraction of water than what can be contained by the gasohol mixture, phase separation of the gasohol mixture will occur.
This produces abnormal combustion and leads to engine knocking that can potentially damage the engines. On the other hand, ethanol is known to increase the corrosion of the engine and fuel system materials due to soluble contaminants such as chloride ions.
However, it has been shown that the addition of water can help to prevent corrosion as well, but the fraction of water has to be carefully controlled to avoid phase separation. We should also mention that in some countries, Brazil for example, the use of gasohol blends with higher percentages of ethanol is legal. Therefore, the gasohol blend and their water content should be monitored not only when the blend is distributed, but also in real time when gasohol is being used.
There are a few techniques to detect alterations in gasoline either due to adulteration or ethanol incorporation, such as the incorporation of chemiresistors for ethanol detection in hydrocarbons [ 4 ], piezoresonance elements [ 5 ], and the use of sensor arrays based on mass and capacitance transducers [ 6 ].
However, for security reasons, it is highly desirable that such sensors avoid electrical signals due to the contact with flammable or explosive substances. There are other options based in selective colorimetric indicator films called Wetting In Color Kit WICK [ 7 ], but chemical interference presents gaxohol significant inconvenient as a sensing element. Optical fiber sensors OFS are ideal for this task because they do not require electrical signals to operate.
In addition, OFS are compact, immune to electromagnetic interference, exhibit high sensitivity, with good portability and low cost. The majority of the OFS involved with fuel detection has been focused on hydrocarbon leak detection [ 8 — 11 ].
There are few reports dealing with the detection of the percentage of ethanol and other contaminants in gasoline [ 12 — 14 ].
A particular technique relies on the extraction of analyte molecules into a hydrophobic silicone cladding that covers an optical fiber and the measurement is performed via absorption changes of the evanescent field [ 12 ]. The main drawback is that the response time is large and the fiber requires additional preparation. Other reports take advantage of the ability of long period gratings LPG to measure the refractive index RI of liquids as a way to detect mixtures of ethanol and gasoline [ 1314 ].
The only drawback in this case, is the need to inscribe the LPG which requires complex equipment and could impact the final cost of the sensor. A device that has attracted a great deal of interest on the development of fiber sensors is the one based on multimode interference MMI effects. The key advantages of MMI fiber sensors are that they are quite simple to fabricate and relatively inexpensive.
Therefore, fiber sensors based on MMI structures have been developed to measure different variables such as temperature, curvature, vibration, liquid level, as well as MMI refractometers [ 15 — 21 ].
In this paper we demonstrate efficient quality control gasouol a variety of gasohol blends using MMI fiber sensors. As we previously explained a dxperiment gasohol blend is defined by the volume concentration of ethanol incorporated into the blend. Considering that ethanol has a smaller refractive index than gasoline, we expect that gasohol blends with higher ethanol content will exhibit a smaller RI than gasoline.
Since MMI sensors are capable of detecting small RI changes, accurate control of gasohol blends is realized in a simple way. Additionally the sensor is capable of detecting when water incorporated in the blend has exceeded the maximum volume tolerated by the gasohol blend, which is responsible for phase separation of the ethanol and gasoline.
We should highlight that since the sensor does not require any particular coating and its fabrication is rather simple and inexpensive. Therefore, if the MMF is cleaved to a particular length, which coincides with the position where an image is formed, light with a specific wavelength will be coupled to the SMF output and transmitted through the MMI device. Any other wavelength value that deviates from the design wavelength will form its image before or after the MMF-SMF interface, and the light coupled to the output SMF will be attenuated as shown in Figure 1a.
The relation that defines the transmitted MMI peak wavelength is well known and is given by [ 19 ]:.
Gasohol – Definition, Glossary, Details – Oilgae
As shown in Equation 1the peak wavelength can be shifted when the effective RI and diameter are modified, which tasohol be achieved via the evanescent field of the propagating modes. Therefore, when the MMI device is immersed in a liquid, such as gasoline, ethanol, or gasohol in our case, the index contrast between core and liquid cladding will be reduced which increases the effective diameter and RI of the fundamental gashool. The net result is that the MMI peak wavelength will be shifted to longer wavelengths as the RI of the liquid is increased.
Since there is a significant RI difference between gasoline and ethanol, gawohol effect can be used to evaluate the quality of gasohol mixtures. In order for the MMI sensor to discriminate the gasohol mixtures the spectral separation between the transmitted MMI peaks when the No-Core fiber is surrounded by ethanol and gasoline has to be clearly identified. The length of the No-Core fiber was taken as We also included other RI values to obtain a better curve.
As shown in Figure 1b in the case of ethanol the transmitted peak is located at The peak-to-peak difference of 21 nm should be enough to identify different gasohol mixtures whose MMI peak wavelength will fall within this range. Nevertheless, as will be shown later, we can exprriment increase esperiment sensitivity by reducing the diameter of the No-Core fiber.
Gaasohol a microscope and a micrometer stage we align the splicing point with the edge of the cleaver knife, and the fiber is then moved away a distance of We should highlight that the surface of the No-Core fiber should be free of any polymer that could interfere with the measurements. Therefore, after fabrication, the MMI device was cleaned using a sulfuric acid solution expeirment to remove any residual polymer. The experimental setup for testing the MMI gasohol sensors is quite simple and is shown in Figure 2.
The MMI structure was fixed into a channel engraved in a Delrin plate with integrated liquid inlet and outlet channels. As shown in Figure 3a glass cover was glued on top of the Delrin plate in order to seal the channel.
MMI sensor fixed into the Delrin channel with glass cover a without gasohol and b with gasohol. Red dye is added to the gasohol solution to highlight the gasohol in the channel. Such small variation does not significantly alter the response of the sensor.
It is important to mention that in Mexico we have two different kinds of gasoline with 87 and 92 octane, named G87 and G92 respectively, and both are free of ethanol. Therefore, in order to obtain different gasohol blends, we prepared different mixtures of G87 diluted with anhydrous ethanol AE as shown in Table 1.
The mixtures were selected according to the different gasohol blends that are commonly used in several countries [ 1 — 3 ]. We should also highlight that AE was used to guarantee that the gasohol blends do not contain or will absorb water. Although the results reported here were performed using the G87 type, similar results should be obtained with the G92 type. We believe that similar results should be obtained for other types of gasoline used worldwide.
Gasohol blends prepared using anhydrous ethanol and G87 gasoline. The blends are labeled following standard convention. As shown in Figure 4awe have a separation of Such a difference is related to the fact that the RI of ethanol and gasoline used in the simulations are not necessarily the same for AE and G87 gasoline.
Gasohol: Facts, Figures and Common Blends
Nevertheless, the peak wavelength separation between AE and G87 gasoline should be enough to monitor the different gasohol blends. Gasohol measurements were performed by first gasohll the gasohol blends for a period of 2 min. After mixing, the gasohol was inserted into the channel and the spectral response of the MMI sensor was acquired with the OSA. Before a new measurement the MMI sensor is rinsed with pure ethanol and, after filling the channel with a new gasohol blend, the spectral response is measured again.
The spectral response of the MMI sensor for each one of the gasohol blends, as listed in Table 1is shown in Figure 4b. We can observe that the spectral response of the MMI sensor is shifted to longer wavelengths as the amount of AE is reduced from the gasohol blend. As ezperiment in Figure 4bthe sensor can clearly identify the different gasohol blends.
However, a simple way to slightly enhance the sensitivity of the MMI sensor is by reducing the diameter of No-Core fiber, which effectively increases the interaction between the evanescent field and the gasohol. Using a buffered oxide etching BOE solution, which is a mixture of ammonium fluoride and hydrofluoric acid 6: In this particular case the length of the No-Core fiber was We should highlight that, before etching, the transmitted spectra does not show any noticeable peak related to the image.
As the fiber is being etched, we can observe a well-defined peak appearing from the long wavelength edge of the transmitted spectra. As the etching continues, the whole spectrum is shifted to shorter wavelengths until we reach the desired peak wavelength value.
Gasohol: Facts, Figures and Common Blends – CarsDirect
As shown in Figure 5a the peak wavelength is very close to the design peak wavelength of nm. Here we observe an increment in the peak wavelength difference between AE and G87 gasoline of We measured the gasohol blends using this sensor and, as shown in Figure 5ba sensitivity of 0.
We should also highlight that exprriment response of both sensors are highly ex;eriment. A more critical issue when monitoring gasohol blends is related to the capability of ethanol to absorb water.
As we previously described, there is a maximum amount of water that the blend can hold before phase separation issues occur. This effect can gaasohol easily observed in Figure 6a—d. Figure 6b—dcorrespond to snapshots taken every three second after the bottles have been shaken for one minute. The gasohol blend-water mixture was vigorously shaken before every measurement, then it was introduced into the channel, and the transmitted spectrum is immediately acquired.
We only notice a slight change in the sensitivity which can be related to the different water content. This behavior is related with the formation of small droplets of gasoline and AE with water due to the phase separation, which effectively reduces the RI for the gasohol blend.
This also reduces the effective RI and diameter of the fundamental mode in the MMI device, and the peak wavelength is also reduced. At higher experimennt volume the effect vasohol seen by all the gasohol blends. In fact, since complete phase separation occurs in a matter of seconds for high water volumes, in a real application the sensor can be placed close to the bottom of the gasohol container. In this experimentt the RI seen by the MMI sensor under complete phase separation will be that of the AE with water, which should be very close to that of the AE, and gasohop larger peak wavelength deviation from linearity should be observed.